Images of Mercury, or rather, shapeless posts with a marble head of Mercury on them, used to be erected by the Greeks and Romans where two or more roads met, to point out the way. (Juvenal, viii. 53.)
There are two famous statues of this god in Paris: one in the garden of Versailles, by Lerambert, and another in the Tuileries, by Mellana.
in astrology, “signifieth subtill men, ingenious, inconstant: rymers, poets, advocates, orators, phylosophers, arithmeticians, and busie fellowes.”
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894